I think it's more a case of Rovio not getting there shit together. this was their first port to Android and it seems they failed miserably. perhaps all the advertising code they put in the Android version is partially to blame . BTW i love Angry Birds, great game. it's now going to be ported to Xbox, Ps3, Wii and a tv show
as far as fragmentation goes the other 100,000 apps don't seem to have a problem letting people know which apps work with which phones.
Android Market only displays compatible apps for the phone you are using. Rovio attempted to circumnavigate the Android Market initially and put it up on another site for downloads and as soon as they found out the other site couldn't handle the demand they then put it on Android Market
In the iTunes store not all apps are compatible with all Apple OS
example RageHD released today a large number of people are experiencing crashes, requirements were ios 3.1 which has now been changed to 3.2 oh yea there was also a warning that anyone running it on anything less that 3gs will experience memory issues.
another update is if your not running in native english the game won't run lol but you have to dig to find that warning
seems like a fucking train wreck to me. itunes is charging 1.99 for RageHD Android is charging NOTHING for Angry Birds
oh BTW be sure to check the comments on iTunes for RageHD lol